/* 去除浏览器默认样式*/
*{
    margin:0;
    padding:0;
    box-sizing:border-box;
}
/*设定页面高度*/
html,body{
    height: 100%;
}
body {
    background-image: url(../img/1.jpg);
    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;
}
/*设置导航栏的样式*/
.nav .spaner {
    /* 相对于父元素的宽度, 如果父元素(.nav) 宽度是 1000px, 此时 .spacer 就是 700px */
    width: 90%;
}
.nav{
    height: 50px;
    background-color: rgb(50,50,50);
    color:rgb(255, 255, 255);
    display: flex;
    align-items: center;/*垂直居中*/
    padding-left: 20px;
}
.nav a {
    color: white;
    text-decoration: none;
    padding: 0 10px;
}